Hematopoiesis and Regulatory Signaling in Molluscs

462 Abstracts / Fish & Shellﬁsh Immunology 91 (2019) 421e472

Keywords: Mollusc; Immune recognition; Pattern recognition theory; Fisheries College, Guangdong Ocean University, Zhanjiang, Novel patter receptors; Mucosal recognition Guangdong, PR China

# Corresponding author. Abstract E-mail address: [email protected] (L. Song). Immunological rejection of the pearl oysters following nucleus implantation is a major issue limiting the successful rate of cultured pearls. To date, the molecular mechanism of immune tolerance during pearl formation in the pearl oysters is still largely unknown. Through the RNA sequencing platform and comparative transcriptomic analysis, we investigated the O-110. chronic gene expression changes at seven time points (0, 5, 10, 15, 20, 30, Hematopoiesis and regulatory signaling in molluscs 60 days post implantation or dpi) over a period of 60 days following nucleus implantation in the pearl oyster Pinctada martensii. A total of 81,390 Xiaorui Song 1,3, Weilin Wang 1,3, Linsheng Song 1,2,3,#. unique transcripts (or unigenes) with a combined length of 96.8 million bp and a N50 value of 2,227 bp were obtained. When compared with se- 1 Liaoning Key Laboratory of Marine Animal Immunology, Dalian quences in the nr, nt, Swiss-Prot, KEGG, COG and GO databases, 36,380 Ocean University, Dalian 116023, China unigenes can find homologous genes. Pairwise comparison of gene 2 Functional Laboratory of Marine Fisheries Science and Food expression among all the samples showed that the largest number (or Production Process, Qingdao National Laboratory for Marine Science 6,846) of differentially expressed genes was observed at 10 dpi. The and Technology, Qingdao 266200, China number then decreased to below 5,000 at 15, 20 and 30 dpi and increased 3 Liaoning Key Laboratory of Marine Animal Immunology & Disease again to 6,679 at 60 dpi. PCA analysis further showed that the seven time Control, Dalian Ocean University, Dalian 116023, China points can be roughly divided into four groups. Comparative transcriptomic analysis between the four groups identified a variety of genes Abstract showing differential expression at different time points, including many Hematopoiesis is a complex process by which different blood cells are immune-related genes such as those encoding for toll-like receptor, lectin, formed and released from hematopoietic tissues. Due to lack of oxygen- scavenger receptor, and peroxidase. In addition, GO and KEGG enrichment carrying erythrocytes and blood cells of the lymphoid lineage, which are analysis revealed that these differentially expressed genes were mainly participating in adaptive immune defense, hematopoiesis in invertebrates associated with metabolism, ribosome function, immune response, offers a simple model system to study regulation of the blood cells of the signaling transduction, and cytoskeleton organization. Notably, two KEGG innate immune system. Several transcription factors have been charac- pathways, namely “cell adhesion molecules” and “primary immunodefi- terized as hemocyte-specific markers in molluscs, such as Tal-1/SCL, ciency” were significantly enriched during the whole process. This finding GATA2/3, Runx, CBFb, ETS, and c-Myb, and are conserved across taxonomic indicates that genes in these pathways are likely to play critical roles in the groups from molluscs to chordates. They were highly distributed in the immune tolerance of the pearl oysters. To conclude, the data obtained hemocytes as well as potential hematopoietic tissue gill, and the RNAi of contribute to a better understanding of the molecular mechanisms of Tal-1/SCL, GATA2/3 and Runx significantly reduced the hemocyte renewal allograft induced immune response in the Pearl oysters, and will facilitate rates in the hemocytes and gill tissue. The temporal and spatial expression the development of effective measures to improve the performance of pattern revealed the potential developmental events of hematopoiesis pearl culture. during ontogenesis of oyster, which initially occurred early in blastula Keywords: Pearl oyster, Pinctada martensii, Nucleus implantation, Allo- stage and definitively resided in the dorsal region in trochophore larvae. A graft, Transcriptome cytokine-like factor astakine was identified from Pacific oyster Crassostrea gigas, which could induce the regeneration of oyster hemocytes either receiving an injection of rCgAstakine in vivo, or incubation with rCgAsta- # Corresponding author. E-mail address: [email protected] (H.Y. Liang). kine in vitro. Furthermore, critical components in signaling pathways, such * These authors have contributed equally to this work. as Notch signaling pathway, Wnt signaling pathway, were restricted to the potential hematopoiesis sites in the adult oyster, which hints at a possible role for them during the hematopoiesis. In oyster, three types of hemocytes were morphologically identified and separated as agranulocytes, semi-granulocytes and granulocytes by flow cytometry and Percoll® O-112. density gradient centrifugation. The granulocytes were proved to be the main immunocompetent hemocytes, and there was potential differentia- Immune responses of American oysters to bacterial and parasitic tion relationship among these three sub-population hemocytes. Several challenge fi hemocyte-speci c molecules, such as CgAATase, CgSPSB3, CgCD-9 were Marta Gomez-Chiarri 1,2,3,4,#, Tejashree Modak 1, Erin Roberts 1, fi identi ed, which could be employed as a potential marker for the isolation Rebecca Stevick 2, David Nelson 3, David Rowley 4. of each subtype hemocytes. Above researches of molluscan hematopoiesis 1 may shed light on the study regulation of the blood cells of the innate Department of Fisheries, Animal and Veterinary Science, University immune system in invertebrates. of Rhode Island, Kingston, RI, USA 2 Keywords: Hematopoiesis; Mollusc; Transcription factors; Cytokines; Graduate School of Oceanography, University of Rhode Island, Hemocyte-specific molecules Kingston, RI, USA 3 Department of Cell and Molecular Biology, University of Rhode # Corresponding author. Island, Kingston, RI, USA 4 E-mail address: [email protected] (L. Song). Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA

Abstract The American oyster Crassostrea virginica is an ecologically and econom- O-111. ically important species in the Northwest Atlantic and the Gulf of Mexico. Wild and cultured populations of this organism are impacted by a variety Deep transcriptome proﬁling sheds light on key players in nucleus of bacterial and parasitic pathogens. Taking advantage of the recently implantation induced immune response in the pearl oyster Pinctada martensii assembled sequence of the American oyster, we have performed a transcriptomic characterization of the immune responses of oysters to bacte- * * W. Wang , Y.Y. Wu , Q.N. Lei, H.Y. Liang#, Y.W. Deng. rial and parasitic challenge. Evaluation of the response of C. virginica larvae to probiotics Bacillus pumilus RI0695 and Phaeobacter inhibens S4 showed